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Guide

Lithium conversion: what it costs and what else must change

The battery swap is the easy part. Three other things decide whether a lithium battery lasts ten years or quietly underperforms: how it's charged, how the alternator is protected, and what happens below freezing.

Updated October 22, 2026. Prices checked on the makers' own sites that day.

Disclosure: We may earn a commission if you buy through these links. It never changes what we recommend or what the tools calculate. How we make money.

Myth: lithium is too expensive

Per year of use it is usually the cheaper battery: AGM should only be run down halfway and wears out in hundreds of cycles. Spark Powered has the full lithium vs AGM cost math; here we cover the conversion itself.

What must change

1. Every charger needs a lithium setting

Solar controller, shore charger or converter, and DC-DC charger all need a LiFePO4 profile, or adjustable voltages set to the battery maker's figures (12 V LiFePO4 packs are usually charged at about 14.2 to 14.6 V; use your battery's manual). Turn off equalize and desulfation modes. Lead-acid float settings left as they are will undercharge it.

2. The alternator needs a DC-DC charger

Lithium has very low resistance and will draw as much as the alternator can give, which can overheat it, especially at idle. A DC-DC charger caps the current and charges at the right voltage, even from a smart alternator. How to size one.

3. No charging below freezing

Lithium-ion batteries must not be charged below 32°F (0°C), though they can discharge in colder weather. Most good batteries stop charging on their own in the cold; a self-heating battery such as the Redodo 12V 100Ah Self-Heating (opens in a new tab) ($279.99 when we checked) warms itself first. Or mount the battery inside the heated living space.

4. A fuse that can stop a lithium short

Lithium can deliver thousands of amps into a short circuit. Use a fuse with a high interrupting rating, such as a Class T, within 7 inches of the battery positive. Cable and fuse sizes.

5. A real battery monitor

Lithium holds an almost flat voltage until it's nearly empty, so a voltage gauge tells you little. A shunt-based monitor counts amp-hours and gives a true percentage.

Three conversion packages, priced today

Battery plus the charging, protection and monitoring that should change with it. Cable, lugs and labor are extra.

Weekender: 100 Ah

Fridge, lights, fan and phones for a day or two

Total$596.95

Most vans: 200 Ah

Adds a laptop and a couple of days off-grid

Total$820.95

Long stays: 320 Ah

Remote work, CPAP, a coffee maker

Total$1,127.95

Not sure which? The planner sizes the battery to your loads and picks the cheapest combination that covers them.

Lead-acid vs lithium for the same usable energy (12 V)
AGMLiFePO4
Share of the rating you should useAbout 50%80% or more (we plan on 80%)
To get about 1,000 Wh usableAbout 170 AhAbout 100 Ah
Charging below freezingYes, slowlyNo, unless self-heating or warmed
Needs a DC-DC charger on the alternatorOptionalYes, in practice

Safety first

Fuse every positive wire as close to the battery or bus bar as you can, and use the wire and fuse sizes from a standard table, not a guess. Boats should follow ABYC E-11; anything that touches 120/240 V AC should follow the NEC. Have a qualified installer check any 120/240 V AC or shore power work.

Run the power planner

Battery, solar, charger, inverter, every wire and fuse, and a priced parts list.

Draw your wiring

Drag parts onto a diagram and get gauge and fuse labels on every run.

Questions people ask

Can I just drop a lithium battery in place of my lead-acid one?

It will work, but it won't work well or for long unless the chargers are set for lithium, the alternator is protected by a DC-DC charger, and you never charge it below freezing. Those three changes are the real conversion.

Does my RV converter work with lithium?

Many recent converters have a lithium or LiFePO4 setting. Older lead-acid-only converters tend to undercharge lithium, and any desulfation or equalize mode must be off. Check the converter's label or manual; if it has no lithium mode, a plug-in lithium charger or a lithium-ready converter is the fix.

How much does it cost to convert an RV to lithium?

Our three packages, priced on the makers' sites on October 22, 2026, run from $597 to $1,128 before cable and labor. The battery is about half of it.

Is lithium worth it over AGM?

Usually yes per year of use: you can use most of its rating instead of half, it lasts thousands of cycles instead of hundreds, and it weighs far less. Our sister site Spark Powered runs the cost-per-year math in detail.

Sources

Keep going

Van electrical basics

The six parts every camper system has, how they connect, and a diagram to download.

DC-DC charger sizing

20 A or 40 A, smart alternators, and what an hour of driving puts back.

Best lithium battery for a van

Redodo and LiTime batteries by price per usable watt-hour, BMS current and cold-weather charging.

Boat house battery upgrade

Adding a lithium house bank beside your starting battery without cooking the alternator.